1. Field of the Invention
The present invention relates to an image recording paper medium and an image recording method.
2. Description of the Related Art
As image recording methods for forming an image on a recording medium such as paper based on an image data signal, there are recording methods such as an electrophotographic method, sublimation-type and melting-type thermal transfer methods, and an ink jet method.
In the ink jet recording method, a printing plate is not required, and an image is directly formed on a recording medium by ejecting an ink only to an image forming portion. Therefore, in this method, the ink can be efficiently used, and the running cost is low. Furthermore, a printing device used in the ink jet recording method is relatively cheaper than a printer used in the related art, can be downsized, and reduces noise. In this way, the ink jet recording method has various advantageous compared to other image recording methods.
When an image is recorded on a recording medium by the ink jet recording method, the moisture in an aqueous ink permeates the recording medium. It is known that the moisture permeating the recording medium cleaves hydrogen bonds of cellulose constituting a pulp layer of the recording medium, the cleaved hydrogen bonds are recombined after the moisture dries, and this leads to a phenomenon (curling or cockling) in which the recording medium is deformed.
To prevent the deformation of the recording medium, a method of adding an anti-curl agent such as a saccharide to an ink, a method of forcibly preventing the curling or cockling by using a paper pressing mechanism of a transport portion, and the like have been suggested. However, none of these methods has succeeded in sufficiently preventing the deformation of the recording medium.
Meanwhile, JP2013-180534A discloses that by coating beforehand a recording medium with a liquid composition containing a specific isocyanate compound, it is possible to prevent the deformation of the recording medium at the time of recording an image on the recording medium by using an aqueous ink.